In the modern world there is an abundance of audio and video material in existence with more created daily. Common examples of audio/video material include e.g., songs, movies, television, radio broadcasts, etc. More mundane examples of audio and/or video information include images of scanned documents, tape recordings of court depositions, audio and/or video recordings of business meetings, recordings of communications signals, e.g., recordings such as wiretaps made by the government, etc.
Pre-existing audio/video material, such as old television shows, movies, radio recordings, songs, etc. represent a wealth of information that is often desirable to maintain and preserve for future generations. Similarly, the audio/video information created on a daily basis for entertainment and other purposes also represents information that, in many cases, it would be desirable to preserve for long periods of time if not indefinitely.
Material to be archived can be in any of several analog or digital formats and on any of several types of media. There is a need to organize and store this material so that the content can be preserved and then searched and retrieved for later use. Later use of archived material can require the material be delivered in its original, or close to original, format or a different format.
Long term storage, e.g., archiving, of video and other information presents many problems not the least of which is the introduction of errors into the information by the failure of the storage medium itself over time. For example, film fades over time making it an unsatisfactory long term storage media for movies and other information.
The advent of computers, the relative stability of modern digital storage media, and the ability to correct errors introduced by digital storage, e.g., through the use of error correction codes and other error correction techniques, makes digital storage of information much more attractive than many older storage techniques. The ability to index, easily access, and accurately reproduce data which is stored digitally makes digital archiving of data, including audio/video information an ever more attractive option. Analog audio and video content needs to be digitized if digital archiving of the material is to be performed. This may be achieved by performing digital sampling operations on the analog audio/video information to be archived.
Significant decreases in the cost of digital storage media have further increased the attractiveness of digital storage as an archiving technique. However, given the vast amounts of information that often need to be archived, in many cases the storage of information and the cost of transmitting such information in an uncompressed state still remains impractical. Accordingly, if information is to be archived in a digital form, in many cases there will be a need to use some form of data compression prior to storing the data in the archive.
Furthermore, audio and video content normally needs to be compressed and formatted if one wishes to use modern digital transmission techniques to deliver archived information to an end user. Utilized transmission techniques may include use of the Internet (using Internet Protocol), telecommunication channels such as switched networks, satellites and/or wireless communications system. In each of these cases, very specific compression and formatting steps are often required for data delivery.
While proprietary data compression algorithms may be favored by some companies offering archiving services, the use of proprietary compression algorithms can present problems in regard to future retrieval of the data. In the case of long term storage of data, the company which created the archive on behalf of a client may be out of business by the time the archived information is to be accessed. This can make it difficult to obtain the required decompression programs in a form which can be run on computers which are in use at the time data retrieval and thus decompression is to be performed.
While volume presents one problem with the archiving of audio/video information, the variety of input and output formats which need to be supported create other problems. In many cases, the archived information will have to be output in multiple formats some of which may not even exist at the time the digital archive is initially created. For many users of an archive system, e.g., video archiver's, the ability to output archived information to different formats with little or minimum loss in image quality can be important. However, for other archive users, e.g., people archiving video corresponding to business meetings or court proceedings, a much higher degree of image degradation, corresponding to higher compression and thus reduced storage and transmission costs, may be acceptable.
The ability to search and access an archive is important particularly as the size of an archive increases. Various known data storage systems index data as it is added to an archive but do not include support for indexing additional aspects of the archived information after the archive is created. Such indexing can significantly facilitate the subsequent retrieval of data. Unfortunately, in the case of long term data storage, the information included in an index created at the time of archiving often proves inadequate for previously unforeseen search and retrieval needs.
From the above discussion, it should be apparent that digitized and compressed data can be well suited for archiving, as it can provide reliable long term storage and allows for electronic cataloguing and indexing in addition to computer-assisted functions such as search and retrieval.
Known systems for digitizing audio and video content and producing digital files therefrom normally put the material into the specific end-user format required for a particular application, e.g., radio or television broadcast. Unfortunately, such application formats tend to be optimized for a particular purpose, e.g., to produce a data stream limited by the capacity of a particular communications channel, and not for the purpose of subsequent conversion from the initially generated format to other formats. Accordingly, from an archiving perspective, storage of data in an end user format designed for a particular application is often unsuitable since conversion from the first end user format to another end user format will, in many cases, result in image and/or audio quality significantly below what could have been obtained from the original information source.
With modern systems, the solution has been to preserve the original source of the audio/video data and to re-submit the source for digitization if a new digital format is required for another application or at a later time.
Thus, in known systems, to generate data in another format at a later time requires that the original source of the audio/video content, e.g., the analog film, be preserved for subsequent use or that the data in the original end user format be converted to another end user format which can negatively impact ultimate image quality.
Since storage of information in non-digital form has the problems discussed and, in addition, since re-digitizing of analog source material is an inefficient use of resources since previously performed work is repeated each time a new application format needs to be supported, it is desirable that any digital archiving technique support multiple output formats.
In view of the above discussion, it is apparent that there is a need for improved digital archiving methods and apparatus.